No Arabic abstract
This presentation reports recent results from the hadronic final state in DIS at HERA. Forward jet and $pi^0$ production have been measured by the H1 experiment. The forward jet production cross section shows significant deviation from the predictions based on DGLAP evolution. The forward $pi^0$ data discriminate between different QCD models and are best described by models which take into account the partonic substructure of virtual photons. Inclusive $K_s^0K_s^0$ production in $ep$ has been studied with the ZEUS detector using an integrated luminosity of 120 pb$^{-1}$. Two states are observed at masses of 1537 MeV and 1726 MeV as well as an enhancement around 1300 MeV. The state at 1537 MeV is consistent with the well established $f_2^prime(1525)$. The state at 1726 MeV may be the glueball candidate $f_0(1710)$.
Jet production in electron-proton collisions at HERA provides a unique testing ground for Quantum Chromodynamics (QCD). Apart from the determination of the strong coupling constant $alpha_s$, ep jet data may especially be used to gain insight into the dynamics of the exchanged parton cascade, whose structure is probed by the high-$E_T$ dijet system; thus information on the parton content of the proton and (quasi-)-real and virtual photons is obtained. This report touches some of these aspects revealed in recent jet data from the HERA experiments which are testing perturbative QCD at the limits of applicability.
Recent results from the HERMES experiment at HERA are described. The large data set from Run-I has yielded new information on the helicity structure of the nucleon. The data to be taken in Run-II will deal mainly with the transverse spin structure and with exclusive reactions.
New KLOE results on scalar mesons, $gammagamma$ physics and $eta$ physics are presented.
The high energy programme of the HERA collider ended in March 2007. During the whole HERA programme, a combined total integrated luminosity of 1 fb$^{-1}$ was collected by the H1 and ZEUS experiments. In this context, an overview of the most recent results of both experiments concerning searches for new physics is presented. The topics covered are searches for contact interactions, leptoquarks and excited leptons, as well as studies of the isolated lepton and multi-lepton topologies, and a general signature based search.
Recent results on the searches for new physics in ep collisions at HERA using the ZEUS and H1 detectors are presented. No evidence for excited fermions or supersymmetric particles within the context of the Minimal Supersymmetric Standard Model nor R-parity violation has been found using an integrated luminosity of up to 20 inv pb. New limits have therefore been established.